//////////////////////////////////////////////////////////////////////////
//
//  Copyright (c) 2018, Image Engine Design Inc. All rights reserved.
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//////////////////////////////////////////////////////////////////////////

#pragma once

#include "Gaffer/Context.h"

#include <initializer_list>

namespace Gaffer
{

class Plug;

namespace ContextAlgo
{

/// Utility class for generic access to the equivalent of
/// `ScenePlug::GlobalScope`, `ImagePlug::GlobalScope` and others.
/// This allows utility nodes such as the Switch to avoid "leaking"
/// context variables when evaluating their inputs (the index in the
/// case of the Switch).
class GAFFER_API GlobalScope : boost::noncopyable
{

	public :

		GlobalScope( const Context *context, const Plug *plug );
		~GlobalScope();

		struct GAFFER_API Registration
		{
			Registration( IECore::TypeId plugTypeId, const std::initializer_list<IECore::InternedString> &variablesToRemove );
		};

	private :

		std::optional<Context::EditableScope> m_scope;

};

} // namespace ContextAlgo

} // namespace Gaffer
